The state board of plumbing shall consist of the chief sanitary engineer, or the director of the department of environmental quality, and four persons appointed by the governor. All of the appointed members must have been residents of this state for at least five years immediately preceding their appointment, and one of them must be a master plumber with at least five years of experience in North Dakota, one must be a journeyman plumber with at least five years of experience in North Dakota, one must be a registered professional engineer practicing mechanical engineering in North Dakota, and one must be a representative of the consuming public.